Energy-subtraction Compton scatter camera design considerations: a Monte Carlo study of timing and energy resolution effects

An energy-subtraction Compton scatter camera (ESCSC) was previously proposed for medical imaging applications. This ESCSC consists of a primary detector system (silicon) and a secondary detector system (cadmium-zinc-telluride) for preferred detection of Compton scatter and photoelectric absorption interactions, respectively. To further evaluate the usefulness of this ESCSC for medical imaging, the following characteristics have been simulated: the random emission of gamma rays in time; detector timing, energy and spatial resolution; list mode data acquisition; and post-acquisition coincidence analysis. The resulting optimization of detector characteristics, data acquisition and analysis techniques, and administered activity is presented and discussed. One significant result of these simulations is that a localized activity of about 1.0 mCi allows for recovery of the majority of preferred events while eliminating the majority of 10 and 50 ns FWHM timing and cadmium-zinc-telluride, respectively, are assumed. Consequently, the proposed ESCSC should be capable of acquiring data for administered activities similar to those used with current mechanically-collimated imaging cameras